A dollar bill A dollar bill serial number is a $10-$character string that starts with a letter from the $12$ element set

$\{A,B,C,D,E,F,G,H,$I,$J,K,L\}$ followed by an $8-$digit string $($each digit from the set of $10$ digits

$\{0,1,2,3,4,5,6,7,8,9\}$ and ending with a letter or a star from the $25$ element set:

$\{A,B,C,D,E,F,G,H,$I,$J,K,L,M,N,P,Q,R,S,T,U,V,W,x,Y,***\}$